The present invention relates to packaging machinery and more particularly, relates to high speed packaging machinery for wrapping individual products such as tablets, food products, small boxed goods and the like.
The state of the art in package machinery has progressed to the point where high speed wrapping of individual products is matched with the mass production rate of the products. In order to handle a high volume of small products at the rate in which they are produced, the packaging machinery is generally in continuous motion as opposed to earlier prior art packaging machines characterized by intermittent motion. For example, U.S. Pat. No. 1,392,683 utilizes a pocket wheel which has a plurality of peripheral pockets into which a candy or other product is moved axially of the wheel by means of a set of plungers disposed perpendicular to the plane of the wheel. A wrapper panel is placed over the candy before it is moved into the pocket so that the movement of the candy and wrapper together through an aperture drapes the wrapper over the product. Panel protions extending beyond the pocket are then tucked and folded against the product in the final stages of the wrapping operation. Since the plungers which move the product through a pocket in the periphery of the wheel are fixedly mounted at one point along the periphery of the wheel, the wheel must be momentarily stopped as the product is moved and the wrapping operation is carried out.
Wrapping machines which use intermittently operated wrapping wheels generally have a relatively low production rate. A substantial degree of time and energy is lost in accelerating and decelerating the product between each wrapping of a product. Additionally, the rate at which the product can be accelerated or decelerated may impose additional restraints upon the speed of the wrapping operation even though the machine itself is capable of higher speeds.
U.S. Pat. No. 3,136,104 points out the advantage of higher wrapping speeds permitted by continuously rather than intermittently rotated wrapping wheels. In this patent and in U.S. Pat. No. 1,178,246 the pockets of a wrapping wheel open radially to receive a product. Plungers such as the type shown in U.S. Pat. No. 1,392,683 described above are not utilized and hence the intermittent motion of the wrapping wheels is obviated.
A further advantage of the continuously rotating wrapping wheels is that they permit the use of a rotary folding mechanism that is simpler in construction and faster in operation. Both of the above-identified U.S. Pat. Nos. 1,178,246 and 3,136,104 illustrate rotary folding mechanisms, which include a plurality of folding blades that rotate about an axis situated radially outside of the pockets in the wrapping wheel. The blades are rotated in synchronism with the pockets of the wheel and extend into overlapping relationship with the pockets at the mergence of the blades and wheel. The blades by their operation tuck and fold extending portions of the wrapper panel against the product as it is carried past the rotor toward a discharge point at a further station around the wrapping wheel. The rotary folding mechanisms are completely compatible with the continuously rotating wrapping wheels and are specially suited to high speed operation because of the pure rotational movement of the folding blades which carry out the tucking and folding operations on the wrapper panel. As a result of the rotary motions, inertia forces are very low and, thus, high speed processing of the products is made possible.
It is a general object of the present invention to provide a wrapping machine utilizing a continuously rotating wrapping wheel in order to obtain high speed operation and a correspondingly high production rate. It is a further object of the present invention to provide a high speed wrapping machine capable of handling small individual products such as tablets, food products and the like with a capacity in the order of 1800 pieces per minute.